Air-compressor



(No Model.)

W. A. P.. BICKNELL.

AIR COMPRESSOR. No. 273,014. Patented Feb.27, 1883.

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mm w UNTTi STATES l To all whom tt may concern :l l i Beit known that I, WILLIAM A.P.B10K

State of New York, have invented certain new and useful Improvements in Air-Compressors, of which the following is a full, clear, and exact description. The object of my'invention is to provide certain new and useful improven'ients in aircompressors, whereby the valve leading to the discharge-chamber or com pressed-air receiver will be open when the pressure of the comy pressed air in the cylinder is equal to the pressure ot' the air in the compressed-air chamber, but will not be open to any appreciable extent before that moment, and whereby it will close quickly at the end of thestroke, thus preventing` any Iair from finding its way back as the piston recedes, and whereby said valve may bel proportioned to give good results up to a piston speed of five hundred feet per minute.

The invention consists in a discharge-valve i for air-compressors, which is formed ot' a valve adapted to move in small cylinders or chambers which have one end in communication with a cylinder and the other end in communication with a chamber, which, in turn, 1s in communication with a com pressed-air receiver, whereby the valve will be open whenthe air in the compressor-cylinder has the same pressure as that in the compressed-air receiver, which valve also closes rapidly as soon as the piston reaches the end of the stroke and before it begins to recede. l Reference is to be had to the accompanying drawings, forming a part of this specification, l in which similar letters of reference indicate corresponding parts in all the figures.

Figure lis a longitudinal sectional elevation of one end of the cylinder of an air-compresser provided with my improvements. Fig. 2 is a like longitudinal sectional elevation, ,showing a modification of the same.

The cylinderAcontains the piston B, which y is attached to a piston-rod, B', and is recipro- "cated in the cylinder,as in air-compressors of 'zgthe usual construction. The cylinder is provided with inlet-ports (3,' which are closed by an inwardly-opening spring-valve, D, of any ifable construction. The compressed air Y 'se `out ofthe cylinder through the ports SPECIFICATION forming part of Letters Patent No. 273,014, dated February 27', 1883.

Application filed September 19, 1882. (No model.)

NELL, of'Riverdale, in the city, county, and.

mounted on the same spindlefwith two pistons.

PATENT ChristenJ WILLIAM A. P. BICKNELL, O RIVERDALE, NEW YORK COUNTY, NEW YORK.

AIR-COMPRESSOR.

E 'E into a chamber, S, which ports E E canA be closed by a valve,'I mounted on a spindle, I, which is mounted i 1 such a manner that it can slide in the direction of the length of the cylinder. -A spring, V, surrounding the spindle I, presses the valve'F toward the outer surface ofthe end ofthe cylinder.

The tube J conducts the compressed airfrom the chamber S to the receiver for compressed air. Adjoining the chamber S a chamber, K, is formed, which contains two pistons, L and M, which are made integral, and are mounted on the spindle I, the piston L being larger than the piston M. The said chamber K is of such size that the disks L and M tit closely therein; but both can have a slight movement in the direction of the length of the spindle I. By means ofa channel, m', that partofthe chamber K between the smaller piston M and the wall of the chamber is in communication with the chamber S, and by means ofthe tube G that part of the chamber K between the larger piston L and the wall of the chamber is in communication with the cylinder-A. The distance from the cylinder end of the channel G to the nearest inner end surface of the cylinder must be greater than the thickness of the piston B, so that when the piston B rests against the end of the cylinder the piston will not close the channel G. The channel Gr is provided with a cock, H, for a purpose that will be specified hereinafter. By means of a short channel or aperture, u, the outer part of the chamber K is in communication with the outer air.

In the modification shown in Fig. 2, in place of the disk-valve F, a gridiron-valve, h", is used, and itis also attached to the spindle I', on which the pistons L and M' are mounted.

Thel operation is as follows: The piston has been moving in the inverse direction of the arrow c', and has just compressed the air before it to the pressure of the air in the receiver for compressed air.' The pressure upon the pistons L and M is thus the same, for the short cylinders in which they work are in communication with the cylinderAand with the chamber S by means of the channels G and m', the pressure in the chamberiS being the same as the pressure in the compressed-air receiver. The piston L is ot' larger area than the piston M, and the pressure on the same has therefore overbalanced the pressure upon thepiston M IOO and opened the valve F,wl1ich closed the ports E, thus permitting the compressed air to pass through the ports E, the chamber S, and the tuheJ to the compressed-air receiver. When the piston reaches the position shown in dotted lines it has passed beyond the cylinder end ot' the channel G, thus permitting the compressed air to escape from behind the piston L. The pressure on the piston Mean then push the said piston in the direction of the arrow a. thereby pressing the valve F upon the ports E, which are thus closed. The springV closes the valve F in starting the machine when there is no pressure in the compressed-air chamber.

The device shown in Fig.2operates the same as the device shown in Fig. l, with the excepf tion that the spindle I moves at right'angles to the longitudinal axis oi' the cylinder, whereas in the device shown in Fig. lit moves parallel with the same. When the compressor is ruiming at lower speed than that for which itis designed, the valveFwill he opened and closed sooner than is necessary; but this can be remedied by means of the cock H, by means ot' which the transverse area ot' the channel G can be so adjusted that the valve F is opened and closed at the proper time.

By using my above-described improved discharge-valve agreat amount of power is saved, i'or the valve F will always be open, if the pistons M and L are correctly proportioned, when the pressure in the cylinder A is equal to the pressure in the compressed-air receiver, whereas in the compressors provided with the usual discharge-valve, when' running' at high speed,

Ythe pressure in thercylinder often exceeds the pressure in the compressed-air receiver considerably, because ot' the inertia of said valves when closed and the extra pressure in the cylinder required to overcome said inertia and open them quickly, thus causing a great loss of power.

The above-described valve requires no adjustment for different degrees of compression, but will always be self-acting and self-adjusting, and will close rapidly when the piston reaches the end of the stroke.

An additional opening from the channel G into the cylinder, near the head of the same, may be provided to maintain communication between said passage and the cylinder while the pistoirhead is passing the first opening at the completion of its strokes.

Having thus fully described my invention,l claim as new and desire to secure by Letters Patent- 1. The combination, with an air-compressor cylinder, of a discharge-valve-mounted ou a spindle on which are mounted two pistons otf different sizes, which pistons move in short pressor cylinder' and with the compressed-air receiver, and ofdevices for adjusting the trailsverse area ot' the channel connecting one ot' the said small cylinders with the compressedair cylind er,suhstantially as herein shown and described, and forvthe purpose set forth.

3. In an air-cipressor, the combination, with the compressor-cylinder A and piston B,

ot' the dischargevalve F and pistons L M, oi.'v

different diameters, the valve and pistons being on the same spindle, l, chambers S and K, connected by a channel, m, and tube G, connecting the opposite end of the chamber K with the com pressor-cylinder, substantially as described, and for. the purpose set forth..

4. In an air-compressor, the combination, with the compressor-cylinder A and piston B, ot' the discharge-valve F, spring V, and pistons L M, of different diameters, the valve and pistons being on the same spindle, I, chamber l, provided with a channel or opening, n, chamber S, communicating with the chamber K by a channel, m', and tube Gr, provided with a cock, H, and connecting the opposite end ot' l the chamber K with the compressor-cylinder, substantially as described, and for the purpose set forth.

W'M. A. P. BLGKNELL. Witnesses W, S. WALKER, C. Senewicrr. 

